Moistening device for printing-presses



W. B. PITKIN.

MOISTENING DEVICE FOR PRINTING PRESSES.

APPLICATION FILED DEC. 17, 1917.

1 335,026 Patented Mar. 30, 1920.

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ED $TATES PATT OFFICE.

WMTER B. PTTKIN, OF NEW YORK, Y., ASSIGINOR T0 TLANOGRAPI-IIC EQUIPMENTHUMPY, INCORPORATED, OF NEW "YORK, N. 'Y., A CQRPORA'I'ION OF NEW YORK.

MOISTENING DEVICE FOR PRINTING-PRE$SES.

Specification of Letters Patent.

Patented Mai", 30, 1920.

To all whom it may concern:

Be it known that l, WALTER B. PITKIN, a citizen of the United States,and a resident of the city, county, and State of New York, have inventedan Tmprovement in Moistening Devices-for Printing-Presses, of which thefollowing is a specification.

My invention relates to means for moistening or dampening a printingsurface, such, for instance, as a planographic plate, lithographicstone, or other surface, and refers more particularly to a means ofaccomplishing such moistening through the action of steam which iscondensed upon the surface.

Tn general, my invention comprises means for conveniently generatingsuch steam and applying it to the printing surface, where it iscondensed, but it also includes certain auxiliary features, such asmeans for wholly or partially screening the printing surface from theaction of steam so generated, means for removing any excess of moisturewhich may collect upon the plate, etc.

My invention, is applicable to various lrinds of printing presses, such,for instance, as the rotary ofls'et press, in connection with which Thave illustrated it in the drawings, and T therefore do not intend toconfine myself to its application to any particular type of ress.

in the drawings, which are more or less diagrammatic and intended toillustrate one form of my invention only, although it is capahle ofembodiment in many diflerent forms, T have shown,

Tn Figure l, a transverse sectional view of my improvedmoisteningdevice; and

Tn l ig. 2, a side view thereof.

My invention is illustrated in connection with a rotary oflfset press,portions of the press heing indicated diagrammatically.

Referring to the drawings, 1 indicates a form cylinder of a press. Byform cylinder T intend to designate the cylinder upon which the printingsurfaces to he moistened are carried, no matter what the character ofthese printing surfaces is. The form cylinder revolves in the directionof the arrow 52 and is inhed by any suitable inhing mecha nism,indicated by the inlr roller 3. The form cylinder cooperates with theonset cylinder l,

Adjacent to the form cylinder l and in which eatends l mg an open sideadjacent the form cylinder 1. The housing 5 is adapted to contain wateror any other suitable liquid, which water may he maintained at or aboutthe level 6, in any suitable way. The water 6 is heated to the looilingpoint by means of a heating element 7, which may consist of a pluralityof coils of wire of a relatively high resistance, through which acurrent is passed from a source of electricity 8, or if preferred, thewater may be heated loy a steam pipe, or any other suitahle means. Thesteam thus formed ascends and comes directly into contact with theprinting surface carried upon the form cylinder l as it passes in frontof the opening of the housing 5, due to the rotation of the formcylinder, and deposits water of condensation thereon, due to the rapidconduction of heat away from the printing surface, by reason of therelatively large mass of the form cylinder 1.

The temperature of the heating element may be regulated thermostaticallyby any suitable thermostatically operated device, adapted to open thecircuit of the source of heating current 8, or if some other form ofheating be used, to otherwise shut off the heat. Since suchdevices are.in common use and many of them may he applied to this specific purpose,l have not illustrated any such apparatus.

T provide means for wholly "or partially screening the plate from theaction of the steam, since it will he understood that if the press isstationary, the moistening device shonld he shut on, and if the press isoperated at a relatively low speed, a smaller part of the printingsurface should he can posed at one time than would he exposed if thepress were operated at a relatively higher speed. Thus, if it has beendetertill mined that to properly moisten a given por tion of theprinting surface, it should he erposed to the action of the steam for agiven time, the area of the opening of the housing should he restrictedif the peripheral of the form cylinder is decreased.

T have therefore shown means for completely shutting off the printingsurface from the action of the steam, whic comprises a she" l t, rahly ol tough a slot ill in the nous-w ing, extending across substantially itsentire width and runs in grooves or upon rails 11 in the ends thereof.This shutter is entirely removed when the press is started up. The slot10 may be closed by means of a shutter 12, which may be held in closedposition by means of the latch 13.

For partially screening the printing surface, I have shown a curtain 14of flexible material, such as rubber or duck, which is operated by meansof a cable 15, extending through the housing 5. The curtain is rolledupon a spring actuated roller16 attached to the inner wall of thehousing 5. By moving the curtain 14, a greater or less distance acrossthe opening in the housing 5, a reater or less area of printing surfacemay e exposed to the steam as required.

The steam within the housing is preferably kept at about atmosphericpressure, in order to prevent leakage between the housing and the formcylinder, and I have therefore provided a relief valve 17, the tensionof the spring 18 of which is adjusted to approximately a pressure of onepound.

Attached to the upper side of the housing 5 and in close proximity tothe printing surface upon the form cylinder 1 is a Wiper 19, preferablyof soft rubber or some similar material, to prevent abrasion of theprinting surface by reason of accidental contact. The wiper is arrangedin as close proximity .as possible to the printing surface, so as toprevent the escape of steam and to break up any globules of water whichmay be formed upon the printing surface, and to distribute the waterevenly over the printing surface. A similar wiper 20 is provided at thelower end of the housing, so as to prevent the escape of steam and toremove any foreign matter which may collect upon the printing surface.

\Vhile I have only illustrated and described one form of my invention, Ido not intend to confine myself thereto, as it is evident that manychanges may be made without departing from its spirit.

I have referred to the use of steam as a moistening agent and in generalthat will be the preferred arrangement, but water vapor or vapor fromother liquids under some circumstances may be desirable, and these Iconsider equivalents for the purposes ofEthis invention. For instance,on damp days in hot weather the condensation from a body of water in thetank would ordinarily be sufiicient and in that case the heatingapparatus might not be used. Such a .use of the apparatus, however, Iconsider within my invention.

What I claim is:

1. In a. device of the kind described, a printing surface, a housinghaving an opening adjacent the printing surface, and

means for generatin steam within the housing for contact wit theprinting surface.

2. In a device of the kind described, a printing surface and means forexposing the printing surface to steam, comprising a housing having anopening adjacent the printing surface and adapted to contain water, anda heating element immersed therein.

3. In a device of the kind described, a

printing surface, means for exposing the printing surface to steam,comprising a housing in close proximity to the plate and adapted tocontain a fluid, means for boiling the fluid and means for varying thearea affected at one time by the steam generated.

4. In a device of the kind described, a pri'nting surface, a housinghaving an open side adjacent the printing surface and adapted to containa fluid, means for boiling the fluid, and means for partly closing theopen side of the housing. a

5. In a device of the kind described, a printing surface, a housinghaving an open side adjacent the printing surface and adapted to containwater,- means for heating the water in said housing to generate steamfor contact with said printing surface, and means for partly closing theopen side of the housing.

6. In'a device of the kind described, a printing surface, a housingadapted to contain water adjacent the printing surface, a heatingelement immersed therein to boil the water, and means for wholly orpartially screening the printing surface from the steam thus formed.

7. In a device of the kind described, a printing surface, a housingadapted to contain water and havin an open side adjacent the printingsurf ace, means for heating said water to the boiling point, means forwholly or partially screening the printing surface from the vapor thusformed and a wiper in close proximity to the printing surface, forremoving the surplus water of condensation.

8. In a device of the kind described, a printing surface, a housinghaving an open side adjacent the printing surface and adapted to containwater, a heating element immersed therein and adapted to brin the waterto the boiling point, means for w lolly or partially screening theprinting surface from the steam so generated, a wiper located at theedge of the opening of the housing and adapted to remove surplus waterof condensation, and an automatic steam blow-off valve communicatingwith said housing.

In testimony whereof, I have signed my name to this specification thiseighth day of December, 1917.

WALTER B. PITKIN.

